This invention relates to watercraft and more particularly relates to a self-propelled surboard type craft.
Several small, lightweight watercraft, often called "motorized surfboards", have been devised and used in the past. In general, most simply involve the installation of an engine on a surfboard type craft and this engine is ordinarily mounted within the interior of the craft. To allow the engine to breathe, an opening or air intake duct must be provided. If the craft is small and has a low profile, this opening must be close to the surrounding water, which can result in flooding if the craft were partially or completely submerged. Although some previous designs provide a closable valve or other device to exclude water, a means for the engine to breathe while the craft is submerged would be desirable. Such a means in combination with a closable air intake port would eliminate flooding and engine stalling and would allow the craft to be operated in nearly all surf conditions.
Small watercraft generally also incorporate a water-jet propulsion system. The intake port for the water-jet is conventionally an opening located on a central portion of the hull. This can be disadvantageous. The light weight of the watercraft results in a comparatively shallow draft. Consequently, the water intake port is relatively close to the surface of the water. Small vertical displacements, for instance those caused by waves, can momentarily raise the intake port above the surface of the water, with a subsequent loss of forward thrust.
Accordingly, it is a primary object of this invention to provide a watercraft which is small, lightweight and fast.
It is another object of the invention to provide a means for the engine of such a craft to run while it has no access to a supply of air.
It is a further object of the invention to provide a water-jet propulsion system for such a craft, which is less susceptible to a loss of forward thrust due to small vertical displacements.